Intermap's DEM products are 3D raster datasets with elevations captured at 5-meter postings or every 5 meters. They are generated using Intermap's STAR technology (Interferometric Synthetic Aperture Radar), which is mounted to an aircraft. The Digital Terrain Model (DTM) data product represents the bare earth and is derived from the Digital Surface Model (DSM) using Intermap's proprietary algorithm and editing processes. Accuracy statements are based on unobstructed areas of moderately sloped terrain. Diminished accuracies are to be expected in areas of extreme terrain and dense vegetation. The DTM is stored as a contiguous dataset spanning continental land masses where we have captured data. It is available in specific areas of interest or in 15-minute by 15-minute tile areas. For more detailed information, refer to Intermap's Product Handbook at <http://www.intermap.com/Portals/0/doc/Brochures/INTERMAP_Product_Handbook.pdf>.

Purpose:

The DTMs are used as a fundamental layer of information in 3D geospatial analysis and spatial information Decision Support Systems (DSS). Typical applications include storm surge analysis, flood planning and watershed analysis, radio propagation modeling, and contour generation. A number of the priority layers of spatial information recognized by the National Spatial Data Infrastructure may be derived from Intermap Technologies' DEMs including elevation, shoreline delineation, hydrography, slope, and aspect layers.

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 20160729

Ending_Date: 20160807

Currentness_Reference:

The above dates refer to the time of field data acquisition and therefore reflect ground conditions at that time.

Status:

Progress: Complete

Maintenance_and_Update_Frequency: Ongoing

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -144.100210

East_Bounding_Coordinate: -143.646634

North_Bounding_Coordinate: 66.518651

South_Bounding_Coordinate: 66.231208

Keywords:

Theme:

Theme_Keyword_Thesaurus: MEL_Scientific-Engineering_Field_Thesaurus

Theme_Keyword: Elevation

Theme_Keyword: Cartography

Theme_Keyword: Geodesy

Theme_Keyword: Geography

Theme_Keyword: Hypsography

Theme_Keyword: Mapping

Theme_Keyword: Photogrammetry

Theme_Keyword: Stereophotogrammetry

Theme_Keyword: Topography

Theme_Keyword: Radar

Theme_Keyword: Interferometric

Theme_Keyword: Remote

Theme_Keyword: Sensing

Theme_Keyword: SAR

Theme_Keyword: DEM

Theme_Keyword: DTM

Theme_Keyword: DSM

Theme_Keyword: ORI

Theme_Keyword: INSAR

Theme_Keyword: IFSAR

Theme_Keyword: IFSARE

Theme_Keyword: GEOSAR

Theme_Keyword: height

Place:

Place_Keyword_Thesaurus: None

Place_Keyword: Alaska

Place_Keyword: USA

Stratum:

Stratum_Keyword_Thesaurus: MEL_Environmental_Domain_Thesaurus

Stratum_Keyword: Terrain

Stratum_Keyword: Earth

Stratum_Keyword: Surface

Stratum_Keyword: Ground

Stratum_Keyword: First

Temporal:

Temporal_Keyword_Thesaurus: 2016

Temporal_Keyword: August

Access_Constraints: Purchase

Use_Constraints: End User License Agreement

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Intermap Technologies Inc.

Contact_Position: Data Archive Manager

Contact_Address:

Address_Type: mailing address

Address: 8310 South Valley Highway, Suite 400

City: Englewood

State_or_Province: CO

Postal_Code: 80112-5847

Country: USA

Contact_Voice_Telephone: (303) 708-0955

Contact_Facsimile_Telephone: (303) 708-0952

Contact_Electronic_Mail_Address: service@intermap.com

Data_Set_Credit: This data was produced by Intermap Technologies Inc.

Native_Data_Set_Environment:

This data is delivered on interoperable media with metadata. The data set was developed on a Microsoft Windows system using Intermap's propriatory Interferometric Editing System (IES).

The NEXTMap DTM data products are derived using Intermap Technologies' STAR-3 airborne Interferometric SAR data acquisition system. The data for this tile was captured at 25200 feet above mean sea level with a primary look direction of West and the swaths with IDs 139, 203, 207, 227 and 286. Small areas of missing data are interpolated using a continuous curvature spline over non-data areas. In larger areas of missing data, Intermap's proprietary editing process utilizes ancillary elevation data from secondary sources to fill the areas of missing data. Most incidents of missing data are due to radar shadow and layover in high-relief areas such as mountainous regions and highly developed urban areas and correspond to the look direction of the radar. Bodies of water are assigned an elevation which corresponds to the shoreline at the time the data was captured. Areas of null data are assigned the value -10000.

Process_Date: 20161130

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Raster

Raster_Object_Information:

Raster_Object_Type: Grid Cell

Row_Count: 5976

Column_Count: 3201

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Map_Projection:

Map_Projection_Name: Albers Conical Equal Area

Albers_Conical_Equal_Area:

Standard_Parallel: 55.0

Standard_Parallel: 65.0

Longitude_of_Central_Meridian: -154.0

Latitude_of_Projection_Origin: 50.0

False_Easting: 0.0

False_Northing: 0.0

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 5

Ordinate_Resolution: 5

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: NAD83 CORS96 EPOCH 2003.00

Ellipsoid_Name: GRS80

Semi-major_Axis: 6378137.0

Denominator_of_Flattening_Ratio: 298.257222101

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: NAVD88(Geoid09)

Altitude_Resolution: 0.01

Altitude_Distance_Units: meters

Altitude_Encoding_Method: Implicit coordinate

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: 32-bit image

Entity_Type_Definition:

The DEM is a 32 bit image on a 15-minute by 15-minute (lat/long) grid. The origin of the post is center center.